Method for refining used crankcase oil



May 18, 1943 w. D. HARRIS 9 METHOD FOR REFINING USED CRANK CASE OILSFiled may 15. 1942 Patented May 18, 1943 l hNiTE METHOD FOR REFI'NING'USED CRANKCASE OIL William D. Harris, Kansas City, Mo. Application May15, 1942,'serial No. 443,030

2 claims.A I(ci. 19t-1s) This invention relates to a method forrendering available for further use in engines, crank case oil which hasbecome contaminated to an extent which ordinarily would render it awaste product. It has been demonstrated by the pres.

ent inventor that the valuable lubricating properties of oil are notdestroyed after ordinary use in an engine, and in fact it has beenproved repeatedly that such used oil ldisplays a greater stability thanit possessed when it was newly proe duced from the refinery. This isexplained by the action of the engine in supplementing the originalrening process by breaking down the unstable constituents remaining in,newly rened oil through the combined effects of heat and mechanicalagitation. It will follow therefore, that if the contaminatingconstituents of the used oil are removed, the reclaimed oil will'besuperior in at least some respects to freshly rened oil.

Methods for reflning'used oil have been proposed previously in theUnited States- Letters Patent of Aycock and Harris, No. 1,707,671,

granted on April 2, 1929, and Patrick, No.l

1,750,350, granted on Marchll, 1930; and apparatus for carrying out suchmethods has .been

In the methods employed in the prior art, oil in the still is heated toa relatively 'high temperature, and when the distillation is complete,this l heat is entirely wasted. In accordance with this' invention, whenthe oil is drawn from the still, it

' is brought into heat exchange reiationshipwitn a new batch of oil'tobe rened, thereby preheating the new batch with a consequent saving oftime and expense. u

The elements of an apparatus to carry out the steps ofmy method areinterconnected by suitable piping and valves so as to facilitate travelof the oil through the system with a minimum of equipment and handling,and to permit cleansing ofthe parts by the circulation of uid from onereceptacle to another, merely by the operation of a few valves. Themanner of achieving the foregoing objects will be more clearlyunderstood by referring to the accompanying' drawing'which is hereuntoannexed and is s part of this speciiication.

The single ligureis a somewhat schematic eledescribed in United StatesLetters Patent of Hary vation partly brokenaway, showing an apparatus lcapable of performing the present invention, al-

though it is recognized that various forms of apparatus may .beemployed, therefore I only show one which has been demonstratedin`practice to be eiicientforthepurposeintended. The still I0, supported ina suitable frame I2, comprises an outer shell I4 and an inner shell itsuitably spaced from the outer onel vfor insulating purposes. The innershell is constructed to withstand relatively high internal and externalpressures. The still is provided with an inlet opening I8, and an outletopening 2li surmounted by a dome having an' inner wall 22 and an outerwall 24 spaced therefrom by a ilange 26. The dome is covered by a cap28, having suitable threads 30 for connection with a fitting 32 to whicha safety valve 34 and a distillate tube 36 are connected. Throughsuitable ttings, the

opposite end of the distillate pipe is connected t0 the upper end of acondenser coil 38, supported in acondenser tank 40. The lower end of thecoil 38 is connected through a pipe 42 and gage glass 44, with acondensate or dilution tank 46.

Cooling water for the condenser is supplied from a suitable sourcethrough a valve 48 and pipe 50 'to the inlet opening 52 at the lower endof the condenser tank 40, whereupon it passes in countercurrent heatexchange relationship with the coil 3B and emerges through an outletport 54 to a water pump 56 through a pipe 58. The pump 56 dischargesthrough an outlet 60 to a conveniently located sewer connection. Thesuction side of the pump l5l is connected through a pipe 62, stop valve64 and check valve 66 to the upper portion 0f the dilution tank 46 sothat by proper manipulation of the valves, the dilution tank and stillcan be subjected to a partial' vacuum.

The dilution tank is supported upon a bracket -68 projecting from theframe I2, and may be` 'I6l arranged to form a cartridge and dependingfrom the cap 28. One or more electric heating elements 'I6 are ttedthrough the still wall to serve as the source of heat. Each element isenclosed within a casing 80 which is successively coated with nickel andchromium and highly polished to resist corrosion and facilitate clean-`ing. The still is also provided with a clean-out opening 82 which isnormally closed lby a cover 84. Other nttings include a thermometer 86to indicate still temperatures, a drain cock or air in a branched line.

vent 88 in the pipe line 42 between thecondenser coil and the dilutiontank, a drain cock 90 for vthe dilution tank itself, a pressure gage 92in vinsulating material |04. 'I'he bottom of the contact vessel isprovided with an outlet opening |06, which through suitable piping |08and a stop valve ||0, is connected with the intake side of a pump |2.Another opening ||4 is provided near the bottom of the contact vessel,

the lower end of a heat exchange coil 8 supported within a heat exchangeandmixing tank |20. 'I'he upper end of the heat-exchange coil ||8 isconnected through a nipple |22, valve |24, four-way fitting |26 andvalve |28 with an opening |30 formed nearer the top of the contactvessel 98. The lower branch of the four-way tting |26 isconnectedthrough a suitable pipe line |32, a 'l'.-tting |34, and a four-wayitting |36, with the delivery side of the pump ||2. The pipe line |32 isprovided with an intermediate branch pipeA |38 which, throughl a stopvalve |40, feeds a retort washer nozzle |42 pass- 'ing through the cover84. The upper branch of the four-way tting |26 is connected with a pipe|44, containing a stop valve |46, terminating One branch is connectedthrough a stop valve |48 with apipe |50 leading to an opening |52at'the'bottom of the mixing which connects it by a length of pipe l||6with sludge` will settle and the oil will be clear of the carbonparticles.

Assuming that all valves and cocks of the apparatus have been closed,the valve'48 will be opened and circulation begun through the condensertank 40 and the pipe 68 to the pump 66 and discharge through the outlet60 to the sewer. The valve 64 is also opened so as to establishcommunication between the pump and the dilution tank 46, condenser coil38 and stillltl, thereby reducing the still pressure to a sub-`atmospheric value.

The oil to be treated is transferred to the mixing tank preferably, soas to cover the heat exchange coil ||8 and the agitator |62 set inopera-tion. To fifty gallons of such oil there is added 20 to 22pounds-of a sulfuric acid treated clay such as RetroL a well knownproduct of the Filtrol Corporation. 'I'his clay serves to restore theoriginal color to the oil, particularly at elevated temperatures. Afterthese materialshave been thoroughly mixed, lthe bottom oi' the mixingtank |20 is placed in communication with the still I0 byl opening thevalve |48,`whereupon the vacuum created by the punip 56 will elevate themixture intothe still. The valve will then be closed and current will besupplied to the heating element or elements 18. The mixing tank |20 willthen be supplied with a new batchof oil' togbe treated in accordance.with steps to .b e'described subsequently.

As the temperature in the still rises, some water will probably'bedistilled'ofl, and by maintaining tank |20; the other branch includes apipe |54,

which is in .turn branched to connect with the y still inlet opening |8through a pipe |56 on the one hand, and through a stop valve |58 to avcontact vessel feed pipe |60, onthe other. An agitator 62 is suitablyclamped on the wall of the mixing tank |20, with its shaft |64 carryingblades at its lowerend.

. vA by-pass 64 is connected in the line |08 intermediate thecontact'vessel and the valve ||0, which, through a stop valve |66,communicates with the T |34. 'I'he pump delivery line is provided-with apressure gage |68, which may be connected at the fourway fitting |36.The upper branch of the four-way tting' |36 is connected throughla stopvalve |10 with the inlet of a-illter a relatively slight vacuum, all ofthe moisture vcan be removed without experiencing excessive foaming.When rthe still temperature reaches about 8251-F., thedegree of vacuumshould be increased gradually byproperly manipulating the valves, andll1' it appears from the 888e 818.56 u that part of thefoil itself ispassing to the dilu' tion. tank, the cock`88 can be opened to v ent thepress |12. 'I'he outlet of the press'is connected through a stop valve|14 with a filler pipe |16, Y and .through a stop valve |18 ahd pipeline |80 with a nozzle |82 located above the contact vessel 'Ihe usedoil to be refined by the present proc-v ess should be treated first withsulfuric acidin an open vessel. Particularly heavy oil may rel therebyclearing this pipe line of any obstrucquire thinning with kerosene ifthe -best results.

' gallon of acid t'o fty gallons of oil. I'he addi? tion of acid andagitation should be continued jhowever until the carbon particles becomesepa-` rated as distinct specks about the size of a pin head or largerand the oil between the particles is in a clear condition. The thustreated oil is thenpermitted to stand for a period ranging from six toeighteen hours,- during which the acid Then the valves cock -The productremaining in the still requires .ble neutralizing agent system to anextent necessary to correct Athis condition. Bycareful observation ofthe gagel glass, it is lpossible to obtain a maximum degree of vacuum inthe system by the time and still temperature reaches'about 425 F.,depending upon the desired viscosity of the end product. After thenecessary heat has been supplied, the circuiti'to the heater is opened,yet the flow of condensing water! may be continued for a brief period-However. when all of the distillate to be removedhasbeen condensed, thevalve 48 will be closed, which lwill of course, stop the action of thepump 66.: At this point, the-valves |24- and |46 between. the stillinlet and. the contact vessel port ||4 may be openedV for a moment forthe purpose ofsucking air. into the stillI and tions. The vacuum in thesystem is then broken by opening the vent 88 and at this time, thedilution tank46`may be drained by opening the some further treatmentwith reagents. which is carried out in the .contact vessel 98. Into thisvessel there is deposited for each fty gallons of oil being treated,about 8 pounds of a clay of the type vof 200 mesh fullers earth, onesuch product `being known commercially as vReiinoilite Compound #1, andabout 1/2- pound of an oil insolusuch as the material sold oon the openmarket as F. C. D. X.

|46 and |24 are opened to per-fr., mit oil to now from the still intothe heat exf change coil I8, wherein heat is transferred from when theoil level in the tank drops.

the hot oil to the new batch in the mixing tank. The agitator |62 willbe set in operation at this time so as to mix the new batch of oil with20y to 22 pounds of the -Retro1" clay alreadyreferred to, which isdescribed in trade-mark registration No. 304,074 as a chemically treatedcolloidal clay adapted for use as a decolorizing, bleaching, filtering,purifying and absorbing medium.

The hot oil owing through the coil ||8 will pass through the pipe ||6into the contact vessel 98 where it encounters the treating agentspreviously placed therein. When all of the oil has owed from the still,which can be determined by the height of o il in the contact vessel 98or byopening the valve 28, the valves |06A and |24 will be closed andthe valve |28 opened.

nozzle |82 ,is sufciently clear. the valve |18 will be closed and thevalve l|14 opened, so that the completely refined oil will be deliveredthrough the pipe |16 to suitable containers. In the event `oi leakage inthe press, the pipe line |83 from the bottom of the press to the intakeside of the pump is provided. which may be `connected through a stopvalve for breaking and establishing now.

The foregoing process represents a preferredV form to utilize thepresent invention, but it is to be understood that the various elementsde- The-valve ||0 in the, suction line |08 is also opened and operationof the pump ||2 isl started. Oil is then drawn from the bottom of thevessel 98 through pipe |08, valve H0, pump ||2, and returned to thecontact vessel through pipef|32 and valve |28. When this circulation hasbeen established, valve |40 leading to the still lis opened and valve|28 is closed. Then valve |58 is opened so that the hot; oil flushingthrough the still will remove any loose composition which may havesettled therein and cause it to` ow into the 'contact vessel. 'I'hevalve |24 leading to the heat exchange coil ||8 is next opened and thevalve |40 closed. The circulation is now from the bottom of the contactvessel, through the pump and coil, and back into the contact vessel.When the stillhas ceased draining through the pipe |60,

the valve |58 will be closed.

The water pump 56 is again started by opening the valve 48, and when asuiiicient vacuum has been established, the valve |48 is opened to drawthe new batch of oil from the mixing tank into the still. The agitator|62 will be stopped When all Yof the oil has been drawn from thetank |20into the still, the valve |48 is closed and the distillation processwill proceed as before. The valve 24 is then closed and the valve |28opened so that circulation from the contactA vessel to the pump and backto the contact vessel will be re established,.and during all of thistime, the distilled oil is 4being cooled in preparation for its passagethrough the lter press |12.

The valve |10 leading to the lter press and the valve |18 leadingtherefrom arenext opened so that oil from the bottom of the contactvessel passes through the pump, part of it passing Ithrough the lterpress, valve |18, pipe Y|80 and nozzle |82 to the contact vessel, theremainder through the pipe |32' and valve 28 to the contact vessel. Thusvit will. be seen, that by adjusting the valve |28, the pressure of theoil applied to the lter press can be regulated rather readily. When theltered oil discharged from the scribed are not to be construed aslimitations except Where they are set forth in the appended claims.

Having described my invention what I regard y through a conduit intosaid still by the vacuum, y

vaporizing the diluents from the oil in said still. after said diluentshave been vaporized, causing the Vacuum to draw air through saidconduit'to cleanse the same, breaking thevacuum in said still, drawingoi the re-rei-lned oil from said still to a contact vessel, cooling saidre-reiined oil on its Way to said contact vessel by passing it inheat-exchange relation with a batch of oil to be re-rened, thencirculatingy said oil repeatedly in a cyclic path from said contactvessel in heat exchange relation to saidv batch of oil and back to saidcontact vessel, by-passinga portion of said oil from said cyclic pathand discharging it into vthe bottom of said still under pump pressure toremove any deposit in said still, vdischarging said ydeposit; and theby-passed portion of the oil from'the still and returning it to thecyclic path.

2.' Process of re-rening of used oil comprising the following steps:creating a vacuum in a still, causing a body of oil to be treated whichis under atmospheric pressure to be drawn through a conduit into saidstill bythe vacuum, Vaporizing the diluents from the oil in said still,breaking the vacuum in said-still, drawing off the re-refined oil fromsaid still to a contact vessel, cooling said re-reiined oil on its wayto said contact vessel by passingvit in heat-exchange relation with abatch of oil to be re-rened, thencirculating said oil repeatedly in acyclic path from said contact vessel in heat exchange relation to 'saidbatch of oil and back to said'contact vessel,

